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News

Canadian Broadcasters Take Aim at AM IBOC Night OperationWhile few in the states will be surprised to hear of Canadian opposition to AM IBOC digital operation in the MW band, they may take pause upon hearing that both the Canadian Broadcasting Corp. (CBC) and the Canadian Association of Broadcasters (CAB) have filed a joint letter of objection to possible FCC approval for nighttime IBOC digital AM operation in the U.S., based on the claim that such an approval would amount to a treaty violation.

In a direct appeal to officials at Industry Canada, the CBC and CAB authored a terse letter dated Aug. 4, spelling out their concern that "AM IBOC transmissions, especially at night, will very likely result in harmful interference to Canadian signals."

The letter goes even further in claiming "the IBOC operations the FCC is already authorizing do not conform with bi-lateral agreements between Canada and the United States."

Both organizations are asking Industry Canada to inform the FCC that night operation of AM IBOC digital hybrid transmission systems will almost certainly violate existing agreements and should therefore be forestalled until more information is made available to Canadian broadcasters and the international agreements in question are suitably amended.

Technology/Applications

Bird Offers White Paper on IBOC Power MeasurementThe unique challenges facing broadcasters trying to measure total RF power in IBOC DAB broadcast systems have been addressed in a recent white paper written by Tim Holt and Don Huston of Bird Electronic. The paper discusses the results of testing suggesting that new techniques developed by the company can provide an accurate and reliable means of measuring combined digital and analog RF carrier power in a single transmission line.

To understand why traditional FM power measurement techniques fall short in dealing with IBOC digital signals, one has to recognize that an analog FM broadcast signal is relatively constant in amplitude, according to Katie Wright, an applications engineer with Bird. In such systems, conventional directional coupler samples and rectifies RF samples use semiconductor diodes that typically operate in a non-linear portion of their operating characteristic. While this approach works well for constant-amplitude FM or CW carriers, says Wright, the varying peak amplitudes present in IBOC DAB's OFDM digital signals mean that that the diodes are likely to introduce unacceptable errors in sample voltages over that signal's wide dynamic range.

According to the paper's authors, the key to accurately measuring the complex, dynamic signals produced in FM IBOC digital and HDTV systems is to use diodes that are carefully biased to operate in the square-law portion of their operating curve, resulting in greatly increased dynamic range. This technique, coupled with precise temperature compensation and sample line sections that are calibrated with sensing elements as a complete unit, yield a broadband power meter that is up to the digital challenge, claims Wright.

Holt and Huston verified the validity of the new approach by comparing results obtained by routing an HDTV signal through a Bird model BPM-6 in line power meter in line between the transmitter and a calibrated calorimetric measurement device. Calorimetric systems derive their accuracy from the fact that RF power dissipated in a resistance is converted entirely to heat, and can thus be measured with precision, regardless of a given waveform's complex characteristics.

Bird has applied its new technology in two products aimed at digital radio and TV broadcasters. The first is the BPM series of wideband power meters, which include VSWR detection and remote interface functions. The second product is a wide band coupler with a terminating power sensor (Mod. 5000 EX and 5011) that fulfills more basic power measurement requirements.

Wright points out that the new power measurement products are also suitable for measuring total power present at the output of multi-transmitter combiners.

IBOC Workshop to Star at NAB Radio ShowCall it the Woodstock of IBOC: three days of intensive workshops revolving around the theoretical and practical issues facing radio stations converting to Ibiquty's HD Radio system. The workshops are part of the NAB Radio Show, to be held at the Manchester Grand Hyatt in San Diego October 6 - 8. At the workshop, attendees will learn how to plan, budget, and implement HD Radio transmission at their stations from a field of experts representing every facet of the industry, from working broadcasters to product developers and manufacturers.

Sept. 6 will be devoted to signal performance and antenna systems for HD Radio, kicked off by Ibiquity's Scott Stull, and followed by consulting engineers Benjamin Dawson (Hatfield and Dawson) and Ronald Rackley (du Treil, Lundin and Rackley) addressing AM antenna performance. Clear Channel's Tom Cox, Jeff Littlejohn and John Warner will also be on hand to discuss IBOC DAB conversion case studies, as will Steve Fluker (Cox Radio) and Clay Freinwald (Entercom). Offering a look at antenna options will be Bill Hartland (ERI), Henry Downs (Dielectric) and Bob Surette (Shivley Labs). Rounding out the day's sessions will be a regulatory and standards panel discussion of IBOC DAB conducted by the FCC's James Bradshaw, Susquehanna Radio's Charles Morgan, Albert Shuldiner of Ibiquity and Valerie Schulte from the NAB.

On Sept. 7, the focus will shift to transmitters and measurement techniques for HD Radio broadcasts. Speakers from the transmitter sector will include George Cabrera (Harris), Time Hardy (Nautel) and Richard Hinkle (Broadcast Electronics), all of whom will be discussing new developments and product solutions. Providing more real-world experience's with AM and FM IBOC DAB installations will be Greater Media's Paul Shulins and Buckley Broadcasting's Thomas Ray, respectively. In addition, Wendell Lonergen (Nautel), Richard Hinkle (Broadcast Electronics) and Geoff Mendenhall (Harris) will provide a detailed examination of what it takes to convert, operate and monitor an AM HD Radio transmission facility. Advice on IBOC DAB signal measurement will be provided by David Maxon, while Dielectric's John Bisset will counsel broadcaster's on how to develop an effective troubleshooting plan for the new technology.

The final day of the workshop will concentrate on studios, audio and data for HD Radio. Speakers on studio equipment will include Mark Grant (Belar Eletronics), James Haustueck (Harris) and Chad Steelberg (Dmarc Networks). The finer points of refining studio operations for HD Radio will be detailed by Jay Hadrick (Harris), Jeff Detweiller (Ibiquity) and Farnk Foti (Omnia Audio). Foti will also join Mike Starling (NPR) and Jack Wang (E-radio) in a discussion of advanced applications and services. An update on the HD Radio receiver front will be delivered by Mike Bergman of Kenwood USA, following an international look at DAB technologies offered by Patrick Hanchay (Societe Radio Numerique) and Matt Honey (Unique Interactive).

Impulse Radio's Paul Signorelli, who will discuss his company's MAT protocols, will host the closing session of the workshop series.

Workshop participants will not only take away an up-to-the-minute understanding of the current state of the HD Radio revolution, but will also receive an attendance certificate that will provide valuable re-certification credits for SBE cerrtification.

Business

Lantz to Head BE HD Radio Product LineBroadcast Electronics appointed Ted Lantz as product manager for its HD Radio product line. During his 12-year tenure at Broadcast Electronics, Lantz has served in a variety of roles, including applications development for the company's digital audio line.

"Broadcasters today are under a tremendous amount of pressure to cut operating expenses and at the same time, prepare for new opportunities. I see my job as making sure they have everything they need to realize both," said Lantz, who started his new role with Broadcast Electronics in August as manager of the company's line of HD Radio transmitters and new data management suite, the Radio Data Dimensions System (RDDS).

BE believes that Lantz's background in digital content management will complement the company's HD Radio RF team, including BE vice president of RF systems Tim Bealor and BE RF director of engineering Richard Hinkle.

IBOC Across America

IBOC by State: PennsylvaniaIbiquity has a list of stations that have licensed HD Radio technology and notes those that are on the air now. IBOC by State will look at various states and list the stations that are making the transition.

Station

Format

Market

Owner

On Air

WJAZ-FM 91.7

Classical/Jazz

Harrisburg-Lebanon-Carlisle

Temple University

No

WHYY-FM 90.9

News/Talk/Info

Philadelphia

WHYY

No

WLDW-FM 96.5

CHR

Philadelphia

Beasley Broadcast Group

No

WMGK-FM 102.9

Classic Rock

Philadelphia

Greater Media

No

WMMR-FM 93.3

Rock

Philadelphia

Greater Media

No

WMWX-FM 95.7

Hot AC

Philadelphia

Greater Media

No

WPEN-AM 950

Big Band

Philadelphia

Greater Media

Yes

WRTI-FM 90.1

Classical/Jazz

Philadelphia

Temple University

No

WRTL-FM 90.7

Classical/Jazz

Philadelphia

Temple University

No

WRTX-FM 91.7

Classical/Jazz

Philadelphia

Temple University

No

WWDB-AM 860

Bus News

Philadelphia

Beasley Broadcast Group

Yes

WXTU-FM 92.5

Country

Philadelphia

Beasley Broadcast Group

Yes

WDUQ-FM 90.5

Nws/Jaz/Inf

Pittsburgh

Duquesne University

No

WRTY-FM 91.1

Clscl/Jazz

Wilkes Barre-Scranton

Temple University

No

WARM-FM 103.3

AC

York

Susquehanna Radio

No

HD Radio Terminology

An Introduction to the New Language Surrounding HD Radio

OFDM: Orthogonal Frequency Division Multiplexing, the modulation scheme used in the transmission of digital information in Ibiquity's FM HD Radio architecture. OFDM is a parallel modulation scheme in which the data stream simultaneously modulates a large number of orthogonal subcarriers. Instead of a single, wideband carrier at a high signaling rate, OFDM uses a large number of narrowband subcarriers that are simultaneously transmitted at a much lower composite symbol rate. The long symbol times of OFDM provide superior robustness in the presence of multipath fading and interference. OFDM is also inherently flexible, allowing the mapping of specific logical channels to different groups of subcarriers.

The peak power in OFDM subcarriers and their sidebands vary over frequency, meaning that Hybrid FM IBOC DAB signals must be amplified using broadband, linear amplifiers, as opposed to the non-linear class C amplifiers traditionally employed in the output stages of high power analog FM transmitters. The complex and dynamic characteristics of ODFM signals also mean that conventional directional couplers are unsuitable for power measurement in IBOC DAB systems.

Products

Ibiquity Certifies TBK's Latest IBOC Receiver ModuleIbiquity's has certified TBK's TDI 2003-A1 decoding module for use in automotive and home HD Radio receivers. The module is the first in the company's line to utilize Texas Instruments' second-generation DRI300 chipset.

The new modules claim to satisfy the single major concern of current and would-be HD radio receiver producers: cost. Key to savings is the modular systems integration approach of the TDI 2003-A1, which allows receiver manufacturers to bolt-on a single package that provides HD Radio decoding combined with MP3/WMA functionality.

Uncertainty about which types of formats will ultimately be implemented by HD Radio broadcasters, such as surround sound or secondary audio channels, will not be an issue for OEM vendors who incorporate the TDI-3000 A1, says TDK, because the DSP used in DRI 1300 chipset is fully software-addressable.

To receive these articles twice a month in your e-mail, subscribe to the IBOC Update - Insight on HD Radio e-newsletter. Click here to subscribe.